Cross-type limit switches comprise a cruciform actuating lever that is actuated via stops arranged along an operating path. DE 1 112 182, for example, shows a limit switch comprising a multi-arm actuating lever that is connected to a lever shaft that, at the same time, acts as a switching shaft. Fastened to said shaft are switching cams that are brought into engagement with an appropriate number of switch contacts. Furthermore, arranged on this shaft is a detent disk that ensures that the limit switch engages in defined positions. Due to the lever shaft and the switching shaft being of the one-piece type, it is not possible to distinguish between a 0° and a 360° position of the actuating lever.
Other limit switches are shown in document WO 2012/065955 A1. Here the limit switch comprises a gear mechanism that is coupled with an input shaft, wherein the gear mechanism drive is coupled with a cam shaft. The limit switch comprises an additional angle-measuring device for measuring the angular position of the input shaft.
The aforementioned limit switches are suitable for use in non-explosive environments. In contrast, in explosive environments the components of a limit switch must comply with a certification guideline for explosion protection. Retrofitting a limit switch with an already certified housing with a gear mechanism may either be impossible because of space problems or necessitate a comprehensive new design.
DE 1 797 089 shows a gear drive comprising several pinions and wheels in a closed housing for running gears in precision engineering. Respectively one pinion and one wheel are coaxially combined in one unit, wherein the units of pinion and wheel are directly supported in cutouts of the housing, with the cutouts matching the form of the units. The gearwheels are supported without axles and shafts on their flat sides and tooth tips.